Model aeroplane holding device

ABSTRACT

A pedal-operated holding device for a model aeroplane, comprising a holding means ( 3; 103 ) having a holding state in which it is arranged to engage part of a model aeroplane ( 20 ), and a release state in which it is arranged to release the part of the model aeroplane ( 20 ); a pedal ( 2; 102 ), the operation of which causes the holding means ( 3; 103 ) to switch between states; and a base ( 1; 101 ), on which are mounted the pedal ( 2; 102 ) and the holding means ( 3; 103 ); in which the holding means ( 3; 103 ) is arranged so as to prevent movement of the model aeroplane ( 20 ) in a first horizontal direction ( 17; 117 ) when in the holding state, and to permit such movement in the release state; and the holding device ( 3; 103 ) further comprises auxiliary stop means ( 156 ) arranged to prevent movement of the model aeroplane ( 20 ) in a second horizontal direction opposite to the first horizontal direction ( 17; 117 ), in which the holding means ( 3; 103 ) is sized and shaped so that the part of the model aeroplane ( 20 ) which it engages is a rearmost pair of horizontal surfaces on the model aeroplane ( 20 ), such as a tailplane.

This invention relates to a model aeroplane holding device, and a method of using the same.

Flying model aeroplanes (also known as model airplanes or model aircraft), and in particular powered radio controlled model aeroplanes, is a popular pastime, in which unmanned, powered and flightworthy scale models of aeroplanes are flown for recreation purposes.

At present, for radio controlled model aeroplanes, starting up and launching these aeroplanes requires two people, because the aeroplane must be securely held whilst it is started up, to prevent the model aeroplane from moving in an unexpected manner. Furthermore, it is not permitted to have any strap of the remote control transmitter (that is, the device held by a user in order to control the model aeroplane) attached round one's neck whilst starting a model aeroplane, in case the strap catches on the propellers or other drive means of the aeroplane. The inventor has therefore appreciated that to reduce the need for a second person other than the person controlling the model aeroplane is desirable; clearly, to do so is more efficient.

According to a first aspect of the invention, there is provided a pedal-operated holding device for a model aeroplane.

Accordingly, such a device can reduce the need for an extra person to hold a model aeroplane before launch, because a single user can release the model aeroplane; the device can hold the model aeroplane whist the user is holding and operating a remote control device, and because the device is pedal operated, the user can operate the holding device whilst operating the remove control device.

Typically, the device will comprise a holding means having a holding state in which it is arranged to engage part of a model aeroplane, and a release state in which it is arranged to release the part of the model aeroplane. Typically, the device also comprises a pedal, the operation of which causes the holding means to switch between states. Additionally, the device may comprise a base, on which are mounted the pedal and the holding means.

The holding means may be arranged so as to prevent movement of the model aeroplane in a first horizontal direction when in the holding state, and to permit such movement in the release state; typically, the first horizontal direction will a forwards direction of the model aeroplane. As such, the device may comprise auxiliary stop means arranged to prevent movement of the model aeroplane in a second horizontal direction opposite to the first horizontal direction. This is advantageous, as it will typically prevent backwards movement of the model aeroplane on the ground; the model aeroplane will therefore be trapped securely between the holding means and the auxiliary stop means when the holding means is in the holding state, thus allowing the user to start the model aeroplane's engine without fear of the aeroplane moving forwards or backwards.

The auxiliary stop means may allow passage of the model aeroplane in the first horizontal direction; control over whether the model aeroplane can do so will typically be provided by the holding means.

Preferably, the holding means is sized and shaped so that the part of the model aeroplane which it engages may be a rearmost pair of horizontal surfaces on the model aeroplane, such as flight surfaces such as a tailplane; herein “horizontal surface” includes any surface extending at least partially horizontally from the body of a model aeroplane. As such, the holding means may comprise a pair of holding members, spaced apart so as to each engage one horizontal surface of the pair of horizontal surfaces; the space between the holding members may allow for the passage of a fuselage of the model aeroplane to pass. The spacing between the holding members may be variable so as to allow for differently-sized model aeroplanes.

The holding members may each be an elongate member having a pivoting end at which they are pivotally mounted on the base. The holding and release states may represent the holding members being at different angles of pivot relative to the base; typically, the holding state will represent the case where the holding members are closer to normal to the base than in the release state. With the base laid on a horizontal surface in use, the holding members may be closer to vertical, or be substantially vertical, in the holding state, and closer to horizontal, or be substantially horizontal, in the release state.

The holding members may be of variable length; typically they could be telescopic. This allows model aeroplanes of differing sizes to be held by the present device.

The auxiliary stop means may be arranged to engage the landing gear of the model aeroplane. The auxiliary stop means may comprise at least one, and preferably two or possibly more arms pivotally mounted on the base so as to have a range of rotation having a limit; the or each arm being arranged so that pushing the arm in the second horizontal direction pushes the arm against the limit, but pushing the arm in the first horizontal direction causes it to rotate relative to the base into a position where it does not impede the movement of the model aeroplane and will typically be flush with the base. The or each arm may be provided with a cross piece extending from the arm, which will typically in use engage part of the model aeroplane, typically the landing gear.

The device may further comprise a cradle for supporting a model aeroplane off the ground. The cradle may comprise at least one flexible elongate member such as a strap or cable which can be attached, typically removably and replaceably, between any two of the holding members and any arms of the auxiliary stop means. Typically, the cradle will comprise two flexible elongate members, which can extend between the holding members and between the arms of the auxiliary stop means respectively. The or each flexible member may be of sufficient length to form a loop between the members to which it is attached.

In this embodiment, the device can be used not only for launching model aeroplanes, but for supporting them off the ground, typically to enable maintenance to be performed thereon. This is particularly advantageous, as it is often necessary to perform unplanned maintenance on model aeroplanes at the airfields where they are being flown, if there is an unexpected crash or heavy landing. Rather than to have to bring a maintenance stand or cradle separate to the holding device, the device with these features means only one device need be brought to the airfield.

The pedal may be linked to the holding means by a linkage which, in the holding state, allows operation of the pedal to move the device into the release state, but will not allow movement of the holding means (typically the holding members) to move the device into the release state.

In the preferred embodiment, the linkage comprises a mechanical linkage, typically comprising a set of links connected together such that, in the holding state, application of a force on the mechanical linkage from the holding means will not cause the mechanical linkage to move the pedal, but application of force on the pedal will cause the mechanical linkage to move the holding means.

The mechanical linkage may comprise at least one transmission member, each transmission member being connected to at least one of the holding members adjacent to the pivoting end of the holding member, but spaced therefrom, so that movement of the transmission member along its length causes the pivoting member to pivot about their pivoting ends. This transmission member may also be of variable length so as to allow for differently sized model aeroplanes.

The mechanical linkage may also comprise at least one locking link, which is pivotally mounted on the base at a first position along its length and to a transmission member at a second position along its length. The or each locking link may be mounted on the base such that, in the holding state, the locking link is parallel with the length of the transmission to which it is linked. By making the locking link and the transmission member parallel and pivotally mounted together, force applied by the transmission member along its length will not act to pivot the locking link. Alternatively or additionally, the or each locking link may be arranged such that forces applied to it in the holding state by the transmission member by a model aeroplane engaging the holding means tend to pivot the locking link in the opposite direction to that required to move the locking link into the release state.

The pedal may be operatively pivotally coupled to the or each locking link at a third position along the length of the locking link. The pedal may be so coupled to the or each locking link that, when the device is in the holding state, the pedal can exert a force on the locking link that is not parallel in direction to the length of the transmission member. This means that the pedal can be used to move the locking link out of the holding state into the release state.

Alternatively or additionally, the linkage may comprise a hydraulic linkage (typically comprising a first hydraulic cylinder coupled to the pedal, a second hydraulic cylinder coupled to the holding means, and a hydraulic transmission system connecting the first and second hydraulic cylinders); an electric linkage (typically comprising a switch connected to the pedal and an electric actuator such as a motor or solenoid connected to the holding means); or a cable linkage (comprising at least one cable connecting the pedal and the holding means).

The base may be shaped to comprise a cross member, on which the pedal is mounted, from which extend two parallel, spaced apart arms, on the end of each of which is mounted a holding member. This means that a model aeroplane having a rear wheel mounted under the tail can be used, as that wheel can roll between the arms unobstructed. Each of the arms may be of variable length, so as to allow for differently sized model aeroplanes. The arms may pivot relative to the cross member for efficient storage of the device.

According to a second aspect of the invention, there is provided a method of holding and releasing a model aeroplane, comprising positioning the model aeroplane adjacent to a holding device according to the first aspect of the invention in order to hold the model aeroplane, and then operating the pedal of the holding device so as to release the model aeroplane.

Where the model aeroplane has a pair of horizontal surfaces (or substantially horizontal surfaces), such as flight surfaces such as a tailplane, mounted towards the back of its fuselage, the step of positioning the model aeroplane may comprise positioning the pair of horizontal surfaces behind the holding members with the holding device in the holding state, so that the model aeroplane is restricted against forwards movement by the holding members until the pedal is operated. Herein, “forwards” is the direction along the fuselage of the model aeroplane in which the model aeroplane generally flies and “horizontal surface” includes any surface extending at least partially horizontally from the body of a model aeroplane.

By positioning the pair of horizontal surfaces behind the holding members with the holding device in the holding state, we include the situation where the model aeroplane is moved into the appropriate position with the holding device in the release state, followed by moving the holding device into the holding state. Once the model aeroplane is in this position, the or each engine of the model aeroplane can be started.

There now follows, by way of example only, embodiments of the invention, in which:

FIG. 1 shows a perspective view of a model aeroplane holding device according to a first embodiment of the invention, shown in a holding state;

FIG. 2 shows a side elevation of the mechanical linkage of the holding device of FIG. 1;

FIG. 3 shows a plan view of the mechanical linkage of FIG. 2;

FIG. 4 shows a perspective view of the holding device of FIG. 1, in use, in the holding state;

FIG. 5 shows a perspective view of the holding device of FIG. 1, in use, in a release state;

FIG. 6 shows a perspective view of a model aeroplane holding device according to a second embodiment of the invention, shown in a storage state;

FIG. 7 shows a model aeroplane holding device according to a third embodiment of the invention, in a first state;

FIG. 8 shows the holding device of FIG. 7, in a second state; and

FIG. 9 shows the holding device of FIG. 7 in the second state, with straps attached to form a cradle;

FIG. 10 shows a perspective view of a model aeroplane holding device according to a fourth embodiment of the invention, with the cradle maximally separated;

FIG. 11 shows a similar view to that of FIG. 10, with the cradle minimally separated;

FIG. 12 shows a perspective enlargement of the beam of the device of FIG. 10; and

FIG. 13 shows a plan view of the beam of FIG. 12.

FIGS. 1 to 5 of the accompanying drawings show a model aeroplane holding device according to a first embodiment of the invention. This comprises a base 1. On one end of the base 1 is mounted a pedal 2, whilst at the other end of the base 1 there is mounted a holding means 3. The holding means comprises a pair of elongate members 6, pivotally connected to the base 1.

The pedal is pivotally mounted on the base by means of a mechanical linkage 4 comprising a set of links; the pedal comprises a foot-engaging portion 12 mounted on a pair of struts 13. This is connected by a forked transmission member 5 to the holding means. As described below, the arrangement of the device is such that, when the pedal 1 is pressed by a user, the elongate members 6 will pivot about the ends pivotally connected to the base 1 from the essentially vertical position (referred to herein as the holding state) shown in FIG. 1 of the accompanying drawings to an essential horizontal position (referred to herein as the release state).

The mechanical linkage 4 can be seen in more detail in FIGS. 2 and 3 of the accompanying drawings, shown in the holding state. The mechanical linkage comprises two fixed planar and parallel side pieces 7, which extend vertically from the base 1. A pair of elongate locking links 8 are provided, which are pivotally connected to the side pieces at a first position 9 along the length of the locking links 8. The forked transmission member is pivotally connected, at its unforked end, to a second point 10 on each locking link 8, the second point being at the end of the locking link 8 distal from the holding means 3.

The pedal 2 is pivotally connected to a third point 11 on each locking link 8, at the opposite end of the locking link from the second point 10, at a point at the end of each of the struts 13. The pedal 2 is also pivotally connected to a pair of guide links 14, such that a point part way up each strut is connected to an end of a corresponding guide link 14. The opposite end of each guide link is pivotally connected to a respective side piece 7.

The effect of this arrangement is that, if pressure is applied by a user to the foot-engaging portion 12 of the pedal 2 with the device in the holding state shown in FIGS. 2 and 3, the guide links 14 will rotate about their pivot points with the side pieces 7 in the direction shown by arrow 15. The pedal will also cause the locking links 8 to rotate about their first points 9, in the direction shown by arrow 16. The forked transmission bar 5, connected to the second points on the locking links 8, will therefore be pushed generally along its length in the direction 17 generally parallel to the base 1; of course, there will also be a component of vertical movement also.

However, whilst movement of the pedal 2 causes movement of the forked transmission member 5, the converse is not true. Because, in the holding state shown in FIGS. 2 and 3, the locking links 8 are parallel with the length of the forked transmission member 5 (the direction in which forces transmitted by the forked transmission member 5 from the holding means 3 are most likely to be applied), forces applied by the forked transmission bar in the two opposite directions parallel to the length of the forked transmission member 5 (that is in direction 17 and opposite thereto) will not cause the locking links 8 to move.

As discussed above, the holding means 3 comprises a pair of elongate members 6. Each of the elongate members is mounted in a pivoting housing 18, which is pivotally mounted on the base 1 at a pivot point 19. Each forked end of the forked transmission member 5 is pivotally mounted to one of the pivoting housings 18. Thus, when the transmission member is driven in direction 17 by action of the pedal 2, the pivoting housings 18 and so the elongate members 6 will pivot about pivot point 19, eventually lying essentially horizontal to form the release state of the device.

The use of this device can be demonstrated with respect to FIGS. 4 and 5 of the accompanying drawings. In FIG. 4 of the accompanying drawings, the holding device is in the holding state, and a model aeroplane 20 is shown as held with both parts of its tailplane 21 held behind the elongate members 6 of the holding means 3. The user can then safely start the engines (not shown) of the model aeroplane and retire to the position behind the pedal (shown by the position of the user's foot 22). At this point, he can fasten any neck strap that he may have on the radio controller for the model aeroplane. Even if the user were to slip and place the model aeroplane engines on full throttle, because of the locking behaviour of the mechanical linkage 4, the force exerted on the elongate members 6 by the model aeroplane will not cause the locking links 8 to rotate, and so the elongate members will stay in the position shown in FIG. 4—the holding state.

When the user is ready to release the model aeroplane 20, they press with their foot 22 on the pedal 2. This causes the locking links 8 to rotate, therefore allowing the forked transmission member to move, thus pivoting the elongate members 6 about the pivot point 19. The result is shown in FIG. 5, which depicts the release state of the device. The elongate members 8 are now practically horizontal, and present no impediment to the movement of the model aeroplane 20, which is shown as having taxied away. This release of the model aeroplane 20 has taken place with only one user involved, and without the need for a user to hold onto the model aeroplane, which can be a risky operation.

It is to be noted that the base 1 is generally U-shaped, with a cross-member 23 connecting two parallel spaced apart arms 24, so as to define a gap 25 between the two arms 24. This gap allows a model aeroplane 20 with a tail-mounted wheel 26, as shown in FIG. 4 of the accompanying drawings, to be used with the present holding device, with the wheel 26 being received in the gap 25.

In order to allow for differently-sized model aeroplanes to be used with this device, various parts of the device can be made telescopic or otherwise of variable length in order to accommodate the size of different parts of the model aeroplane. The arms 24 and the forked transmission member 5 are also telescopic, so as to allow the length of the gap 25 to be increased or decreased to allow for the distance behind the tailplane 21 of the trailing wheel 26. The length of the elongate members 6 can be varied so as to allow for different tailplane 21 heights. The elongate members are mounted in the pivoting housings 18 by means of telescopic sidepieces 27, which allow the width between the elongate members 6 to be varied, to allow for model aeroplanes 20 with different body widths at the tailplane 21.

Mounting holes 28 are provided in the base to allow pins (not shown) to be placed though the base in order to secure the device to the ground. In a manner akin to tent pegs, the pins should be inserted in the ground at an angle opposing the direction of thrust of the model aeroplane.

The struts 13 of the pedal 2 may be collapsible for storage reasons; The strut may be able to pivot about the point at which it engages the guide links 14, with a stop 30 provided so that the pivoting stops once the pedal is in the position shown in FIGS. 2 and 3 of the accompanying drawings, but allows the strut to be folded in direction 31.

For further economy of space in storage, the second embodiment of the invention shown in FIG. 6 of the accompanying drawings can be used. This embodiment functions largely as above, except that the side arms 54 of the base 31 are hingedly connected to the cross member 53. This enables the entire device to be neatly packaged within a cuboid box.

A model aeroplane holding device according to a third embodiment of the invention is shown in FIGS. 7 to 9 of the accompanying drawings. Equivalent integers to those of the first two embodiments have been assigned the same reference numerals, raised by 100.

In this embodiment, the base 101 is of the form of a telescopic frame, having two telescopic first arms 150 extending from a pedal housing 152. The pedal housing 152 supports the pedal 102. The pedal housing 152 also pivotally supports the first arms; they can collapse together for storage, but in use will be kept spread apart, so as to define a space therebetween, by means of a removable strut 163.

The base 101 also comprises a pair of second arms 153, each second arm being pivotally mounted on the end of the first arms 150 at pivot point 154. The second arms 153 are made of a plurality of universal members 153 a, which can be connected end to end to form a second arm 153 of the desired length.

The holding means 103 again comprises a pair of elongate members 106 (each formed of one universal member), pivotally mounted on the end of the first arms 150. They are connected to the first arms 150 by means of a spring-loaded latch 155. Once placed in the erect position shown in FIG. 7 of the accompanying drawings, the latch will hold the elongate members in position against movement in the direction 117, being the forward direction of a model aeroplane to be held.

The latches are deactivated by an adjustable rod system (not shown) running to the pedal 102. The pedal has a safety catch 164, which must be pressed into the body of the pedal housing 152 before the pedal can be activated. Once the safety catch has been pressed, the pedal 102 can be activated once. Activation of the pedal 102 by a user stepping on it pushes adjustable rods running through the first arms 150 towards the pedal housing 152, releasing the latches 155 and allowing the elongate members to rotate in direction 160 towards the ground under the force of the spring of the latches 155 and lie flush with the base 101. Thus, once the pedal is pressed, a model aeroplane with its tail plane held behind the elongate members 106 will be allowed to proceed in direction 117.

However, this embodiment also has a pair of backstops 156 slidably mounted around the ends of the second arms 153 distal from the first arms 150. These backstops 156 each comprise a telescopic arm 157 pivotally mounted on the respective second arm 153. The arms 157 each carry a cross piece 158. The position of the cross piece can be adjusted by means of sliding the backstop along the second arms 153, adjusting the length of the telescopic arm 157 and by sliding the cross piece 158 relative to its telescopic arm 157.

The telescopic arms 157 are pivotally mounted so as to have a range of movement 159; as such, in the erect position shown in FIG. 7 of the accompanying drawings the telescopic arms 157 will resist movement in the direction opposite to direction 117.

If a model aeroplane is positioned with its tail plane positioned behind the elongate members 106, then the position of the cross members 158 can be adjusted to be immediately behind the landing gear of the model aeroplane. Then, whilst the elongate members 106 are still being held erect by the spring latches 155, the model aeroplane will be secure against movement in both the direction 117 and the opposite direction. The model aeroplane will be held even more securely than in the first or second embodiments.

When the pedal is pressed and the elongate members 106, the model aeroplane can be driven forwards (that is, in direction 117) by means of its own propulsion. The backstops 156 will not provide a significant impediment to forwards movement as, if they encounter part of the model aeroplane, they will simply pivot in direction 160 to lie flush with the base 101.

The device in the state shown in FIG. 7 of the accompanying drawings is particularly suitable for use with petrol-driven model aeroplanes. However, it can be put into the state shown in FIG. 8 by rotating the second arms 153 about the pivot points 154 so as fit within the V-shape formed by the first arms 150; this requires the second arms to be telescoped into a greatly reduced length compared with the situation of FIG. 7.

The cross pieces 158 of FIG. 7 are replaced with padded extension pieces 161; it is to be noted that the elongate arms can also be padded. As such, this embodiment is now particularly useful for use with electric model aeroplanes. Electric model aeroplanes do not require manual starting as petrol-driven model aeroplanes do, and so do not generally require pushing backwards whilst manual starting is taking place. However, by swinging the second arms 153 around as shown in FIG. 8, a soft support can be provided for the rear surface of the elevator of the model aeroplane when the tail plane is held behind the elongate arms 106.

If the extension pieces are set at the same height as the elongate arms, then the device can be used to create a cradle for maintaining model aeroplanes as shown in FIG. 9 of the accompanying drawings. A set of straps 162 is used to create two loops, one extending between the elongate members 106 and one between the extension members 161. Typically the straps 162 will be attached to the end of the members 106, 161 by a hook and loop fastening (such as Velcro®), although any other suitable fastener could be used.

Thus, if a model aeroplane needs urgent maintenance on an airfield, the device can be arranged as shown in FIG. 9, and the aeroplane placed with its fuselage within the loops formed by the straps 162. The model aeroplane can be orientated either right-way up or upside down (or any other necessary orientation) to reach any damage. Thus, the device will also operate as a cradle.

A further, fourth embodiment of the invention is shown in FIGS. 11 to 13 of the accompanying drawings. This develops the cradle concept shown in FIG. 9. Reference numerals for equivalent features have been raised by 100 with respect to FIGS. 7 to 9.

In this embodiment, the extension pieces 261 and the elongate members 206 are once again used to create a cradle. They are provided with looped straps 262, positioned between the pair of extension pieces 261 and the pair of elongate members 206. A moulded cushion 270 is provided on the top and bottom part of each strap, to rest against the fuselage of the model aeroplane.

It is to be noted that the backstops 256 and so the extension pieces 261 can be moved along the length of the first arms 250 in order to change the distance between each set of looped straps 262; in the present embodiment, the distance between the straps can therefore be varied between approximately 620 mm and 1060 mm.

In order to provide greater stability to the cradle, the pair of extension pieces 261 and the pair of elongate members 206 are each joined together by a cross member 271. The cross members 271 are joined together by a telescopic beam 272, made of two slotted sub-beams 273. The two sub-beams each carry a captive locking member 274 at the end distal from the cross piece 271 two which it is attached; this engages a slot in the other slotted sub-beam 273. The locking member comprises a screw 276 held in a hole (not shown) in the distal end of its sub-beam 273, a Belleville-type spring washer 277 held between the two sub-beams on the screw 276, and a butterfly nut 275 on the opposite side of the other sub-beam to the spring washer 277.

Thus, tightening the two butterfly nuts 275 will securely fix the length of the telescopic beam 272; together with the cross members 271, the elongate members 206 and the extension pieces 261 are therefore braced against movement relative to one another, so as to make the cradle more stable. If so desired, a scissor brace 280, shown in dotted lines in FIG. 10 of the accompanying drawings, can be used between the extension pieces 261, so as to provide them with extra strength. 

1. A pedal-operated holding device for a model aeroplane, comprising a holding apparatus having a holding state in which it is arranged to engage part of a model aeroplane, and a release state in which it is arranged to release the part of the model aeroplane; a pedal, the operation of which causes the holding apparatus to switch between states; and a base, on which are mounted the pedal and the holding apparatus; in which the holding apparatus is arranged so as to prevent movement of the model aeroplane in a first horizontal direction when in the holding state, and to permit such movement in the release state; and the holding device further comprises auxiliary stop apparatus arranged to prevent movement of the model aeroplane in a second horizontal direction opposite to the first horizontal direction, in which the holding apparatus is sized and shaped so that the part of the model aeroplane which it engages is a rearmost pair of horizontal surfaces on the model aeroplane.
 2. The holding device of claim 1, in which the auxiliary stop apparatus allows passage of the model aeroplane in the first horizontal direction.
 3. The holding device of claim 1, in which the holding apparatus comprises a pair of holding members, spaced apart so as to each engage one horizontal surface of the pair of horizontal surfaces.
 4. The holding device of claim 3, in which the holding members each comprise an elongate member having a pivoting end at which they are pivotally mounted on the base.
 5. The holding device of claim 1, in which the pedal is linked to the holding apparatus by a linkage which, in the holding state, allows operation of the pedal to move the device into the release state, but will not allow movement of the holding apparatus to move the device into the release state.
 6. The holding device of claim 5, in which the linkage comprises a mechanical linkage, comprising a set of links connected together such that, in the holding state, application of a force on the mechanical linkage from the holding apparatus will not cause the mechanical linkage to move the pedal, but application of force on the pedal will cause the mechanical linkage to move the holding apparatus.
 7. The holding device of claim 6, in which the mechanical linkage comprises at least one transmission member, each transmission member being connected to at least one of the holding members adjacent to the pivoting end of the holding member, but spaced therefrom, so that movement of the transmission member along its length causes the pivoting member to pivot about their pivoting ends.
 8. The holding device of claim 7, in which the mechanical linkage comprises at least one locking link, which is pivotally mounted on the base at a first position along its length and to a transmission member at a second position along its length.
 9. The holding device of claim 8 in which the or each locking link is mounted on the base such that, in the holding state, the locking link is parallel with the length of the transmission to which it is linked.
 10. The holding device of claim 8, in which the or each locking link is arranged such that forces applied to it in the holding state by the transmission member by a model aeroplane engaging the holding apparatus tend to pivot the locking link in the opposite direction to that required to move the locking link into the release state.
 11. The holding device of claim 8, in which the pedal is operatively pivotally coupled to the or each locking link at a third position along the length of the locking link.
 12. The holding device of claim 1, in which the base is shaped to comprise a cross member, on which the pedal is mounted, from which extend two spaced apart arms, on the end of each of which is mounted a holding member.
 13. The holding device of claim 1, further comprising a cradle for supporting a model aeroplane off the ground.
 14. The holding device of claim 13, in which the cradle comprises at least one flexible elongate member such as a strap or cable which can be attached between any two of the holding members and the auxiliary stop apparatus.
 15. A method of holding and releasing a model aeroplane, comprising positioning the model aeroplane adjacent to a pedal-operated holding device for a model aeroplane in order to hold the model aeroplane, the holding device comprising: a holding apparatus having a holding state in which it is arranged to engage part of a model aeroplane, and a release state in which it is arranged to release the part of the model aeroplane; a pedal, the operation of which causes the holding apparatus to switch between states; and a base, on which are mounted the pedal and the holding apparatus; in which the holding apparatus is arranged so as to prevent movement of the model aeroplane in a first horizontal direction when in the holding state, and to permit such movement in the release state; and the holding device further comprises auxiliary stop apparatus arranged to prevent movement of the model aeroplane in a second horizontal direction opposite to the first horizontal direction, in which the holding apparatus is sized and shaped so that the part of the model aeroplane which it engages is a rearmost pair of horizontal surfaces on the model aeroplane; the method also comprising subsequently operating the pedal of the holding device so as to release the model aeroplane.
 16. The method of claim 15, in which the model aeroplane has a fuselage having a front end and a back end and a pair of horizontal surfaces, such as a tailplane, mounted towards the back of the fuselage, wherein the step of positioning the model aeroplane comprise positioning the pair of horizontal surfaces behind the holding members with the holding device in the holding state, so that the model aeroplane is restricted against forwards movement by the holding members until the pedal is operated.
 17. The method of claim 15, comprising the step of starting an engine of the model aeroplane after the model aeroplane is held by the holding device but before it is released.
 18. A pedal-operated holding device for a model aeroplane, comprising a holding apparatus having a holding state in which it is arranged to engage part of a model aeroplane, and a release state in which it is arranged to release the part of the model aeroplane; a pedal, the operation of which causes the holding apparatus to switch between states; and a base, on which are mounted the pedal and the holding apparatus; in which the holding apparatus is arranged so as to prevent movement of the model aeroplane in a first horizontal direction when in the holding state, and to permit such movement in the release state; and the holding device further comprises auxiliary stop apparatus arranged to prevent movement of the model aeroplane in a second horizontal direction opposite to the first horizontal direction, in which the holding apparatus is sized and shaped so that the part of the model aeroplane which it engages is a rearmost pair of horizontal surfaces on the model aeroplane; in which the holding apparatus comprises a pair of holding members, spaced apart so as to each engage one horizontal surface of the pair of horizontal surfaces; and in which the base is shaped to comprise a cross member, on which the pedal is mounted, from which extend two spaced apart arms, on the end of each of which is mounted a holding member.
 19. The holding device of claim 18, in which the pedal is linked to the holding apparatus by a linkage which, in the holding state, allows operation of the pedal to move the device into the release state, but will not allow movement of the holding apparatus to move the device into the release state.
 20. The holding device of claim 18, further comprising a cradle for supporting a model aeroplane off the ground. 